The invention relates to power supplies, and more particularly, to AC power supply apparatus and methods and computer program products for operating the same.
In some power supply applications, such as in uninterruptible power supply (UPS) applications, it may be desirable to synchronize the output of a UPS to an AC waveform reference. For example, in some UPS applications, it may be desirable to synchronize an output inverter of a UPS to a bypass source, such as a utility source or generator, or to a reference AC waveform signal. U.S. Pat. No. 5,745,355 to Tassitino, Jr. et al. and U.S. Pat. No. 6,549,440 to Tassitino, Jr. et al. describe various techniques for achieving such synchronization in on-line UPS configurations.